While I was at iSimangaliso Wetland Park recently, I met up with Xander Combrink, the park’s threatened species expert and herpetologist (that’s a name for someone who studies frogs, toads, snakes and other reptiles).
This World Heritage Site on the north-east coast of South Africa is renowned among conservationists as a very biodiverse protected area, with more species of animals than perhaps any other in Africa. The terrestrial, fresh water and marine environments combine to form an extremely rich ecology.
I went out with Xander and his three sons (Stanis, Anno and Bernard) for a few nights, looking for frogs and snakes to photograph.
As we went splashing through the wetlands in the dark, wearing our head torches and trying not to worry about the crocodiles that were nearby (!), I chatted to Xander about this special place and it’s thousands of smaller species.
“It’s great when the general public, or even conservation managers, become excited about the smaller things,” Xander told me. “Most people just think about the rhinos, elephants or lions and those kind of things.”
“So when someone gets excited about a spotted shovel-nosed frog, that’s a big thing for me. I consider that a major achievement and success in conservation.We have to get the public interested in these things, because otherwise we’re going to lose it all one day to mining, or agriculture and forestry.”
“We must instil a love and interest in people for all wild animals. That’s why the message from guys like Ian Player and Ian McCallum and others is so important. We must restore our link with wilderness. We’re part of nature, and we’ve lost that link in the modern world. We need to go back, we need time in nature to be whole, to be a complete human.”
Scott Ramsay: This park is renowned for its diversity, isn’t it? And why are frogs so important in its ecology?
Xander Combrink: “Yes, even though the park covers less than 0.3% of South Africa’s land mass,” Xander explained, “iSimangaliso has about half of all the frog species in the country, and almost half the snake species.”
“Frogs are bio-indicators, they tell us what’s happening to the ecosystem. Because of their permeable skin, they absorb whatever is in their environment, and they are extremely sensitive to any pollution.
To give you an idea, if you take a frog and you put them in normal tap water that we drink, it will be dead the next morning. They will die from the chlorine. (So remember always to use rain water to put frogs into if you’re studying them).
Maybe unsurprisingly, frogs are the most threatened of group of all animals, globally. They can’t fly like birds, of course, away from a damaged habitat. Frogs will just die out.
Frogs are also very good at controlling mosquito populations. They eat enormous amounts of mosquito larvae, so in Africa where malaria is rife, they’re a natural, free pest control. I don’t think people realize that.
That’s why if you spend time in a natural, untouched wetland area in the middle of Africa, there are almost no mosquitos, but if you go to a town or city, where the frog populations are destroyed, there are plenty of mozzies.”
Frogs are also an incredible food source, including some snake species which feed almost exclusively on frogs. The rhombic night adder, the snouted night adder and the herald snake are almost exclusive frog eaters. Even your forest cobra eats lots of frogs.”
SR: Which are some of iSimangaliso’s special frogs?
XC: “I think all frogs are special, but iSimangaliso has three really special frogs.
Pickersgill’s reed frog (Hyperolius pickersgilli), which is only found in very few populations in KwaZulu-Natal, and nowhere else. It’s critically endangered, because its natural habitat has been so degraded. The population in iSimangaliso is the only protected population in South Africa. They’re a hard frog to find because they don’t call very loudly and they’re small.”
Then there’s the whistling rain frog (Breviceps sopranus), which we have very little data on, because they’re so hard to find, and because their distribution is extremely limited to just this area and north into Swaziland. They have a beautiful high pitched call, which is why their latin name is “sopranus”.
Third, the spotted shovel-nosed frog (Hemisus guttatus), which is a burrowing frog (termed “fossorial”) so it spends almost its entire life under the ground, coming out just for mating and food.
Our more common frogs are just beautiful. Reed frogs (Hyperolius) have unbelievable colours, the leaf-folding frogs (Afrixalus) are golden and delicate. The ornate frog (Hildebrandtia ornata) is a very pretty frog recorded from the Mkhuze section of the park.
The banded rubber frog (Phrynomantis bifasciatus) is an interesting one, because it emits a toxin. So never touch your eyes after you’ve handled one, because you’ll have a severe reaction.
The southern foam nest frog (Chiromantis xerampelina), is fascinating because it can thermoregulate. It sits outside in the midday sun and turns completely white to prevent itself from overheating.
SR: Frogs are making a big comeback in iSimangaliso since the commercial tree plantations were removed from parts of the park?
Yes, for instance, there used to be 6 million pine and gum trees on the western Shores of Lake St Lucia. There were about 14,000 ha of plantations, so that’s14,000 rugby fields!
Now those plantations have been taken out by the park, the trees aren’t sucking up all the water, so the natural wetlands are returning. And the frogs are re-colonising these areas spectacularly. Our frog population is expanding because of the clearing of the alien plants.